Camera shutter mechanism



Dec. 27, 1960 T IER 2,966,102

CAMERA SHUTTER MECHANISM Original Filed 001;. 27, 1953 8 Sheets-Sheet 13 T 82- 63\ l I i I320 IINVENTOR 5 ozia dv ATTORNEYS Dec. 27, 1960 s. B.WHITTIER 2,966,102

CAMERA SHUTTER MECHANISM Original Filed oct. 27, 1953 8 Sheets-Sheet 2I02 HY /76b 8 94: m 94b I HOd I FIG. 3 NT j y fm ATTORNEYS Dec. 27, 1960TT R 2,966,102

I CAMERA SHUTTER MECHANISM Original Filed 001:. 27, 1953 8 Shegts-Sheet3 FIG.5

ATTORNEYS S. B. WHITTIER CAMERA SHUTTER MECHANISM Dec. 2 7, 1960 8Sheets-Sheet 4 Original Filed Oct. 27, 1953 INVENTORI FIG. 7

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ATTORNEYS Dec. 27, 1960 s. B. WHlTTlER CAMERA SHUTTER MECHANISM OriginalFiled Oct. 27, 1953 8 Sheets-Sheet 5 INVENTOR 43% FIG. 8

ATTORNEYS Dec. 27, 1960 s. B. WHlTTlER 7 2,965,102

CAMERA SHUTTER MECHANISM Original Filed Oct. 2'7, 1953 8 Sheets-Sheet 6INVENTOR ATTORNEYS Dec. 27, 1960 s. B. WHlTTlER 2,966,102

CAMERA SHUTTER MECHANISM Original Filed Oct. 27, 1953 s Sheets-Shee'h 7INVENTOR ATTORNEYS Dec. 27, 1960 s WH|TT|ER 2,966,102

CAMERA SHUTTER MECHANISM Original Filed Oct. 2'7, 1953 8 Sheets-Sheet 8-FIG. ll 466 INVENTOR afz dm ATTORNEYS United States Patent CAMERASHUTTER MECHANISM Sidney B. Whittier, Concord, Mass., assignor toPolaroid Corporation, Cambridge, Mass., a corporation of DelawareOriginal application Oct. 27,1953, Ser. No. 388,641, now Patent No.2,877,697, dated Mar. 17, 1959. Divided and this application May 15,1957, Ser. No. 659,313

8- Claims. (Cl. 95-115) This invention relates tov photographicapparatus and more particularly to novel shutter mechanism forassociation with the exposure aperture of a camera.

This application is a division of my copending applica: tion Serial No.388,641, filed October 27, 1953, now Patent No. 2,877,697.

In the copending. application of. Murry N. Fairbank, Serial No. 58,258,filed. November 4, 1948 for Photographic Apparatus (now Patent No.2,662,457), thereis disclosed a novel shutter mechanism of the typecomprising an. aperture-covering element or blade mounted forsubstantially free and frictionless rotation and normally held by asuitable holding means in a stationary aperture-covering position. Theshutter includes, means for, applying a sharp impact to the closureelement to rapidly move the same so asto disengage it fromits holdingmeans and so as to uncover the exposure aperture. There are provided ata predetermined point in the path of movement of the closure elementsuitable rebound means for engaging a portion of said. element forthepurpose of reversing the. direction of rotation of said element so asto return the latter. to aperture-covering position. The time duringwhich the exposure aperture is uncovered depends upon the speed andlength of travel of the element, the length of travel being preferablycontrolled by one or more rebound members positioned along the arcuatepath of anengagement portion of said clement. Means may be provided foradjusting the position of a rebound member in the path of saidengagement portion or for adjusting a plurality of rebound members intoand out of. position for. engagement with theclosure element.

An object of the inventionv isto provide, in a shutter structure of theabove type, a novel flash synchronizing means comprising a free-movinginertia tripper for accurately, controlling the relative timing of theclosing of ailash, circuit andlthe movement of the. aperture-coveringelement.

Other objects of the invention will in part be obvious and will in partappear hereinafter. V

The invention accordingly comprises theapparatus possessing theconstruction, combination of elements and arrangement of parts which areexemplified in the following detailed disclosure, and the scope of theapplication of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

Figure 1 is a diagrammatic plan view of a shutter assembly embodying thepresent invention, the front housing being removed and the shutter beingviewed from the front toward the camera;

Fig. 2 is a diagrammatic sectional view through the shutter of Fig. 1taken substantially along the line 22 and showing in detail a mountingof the shutter blade, diaphragm, and time control knob;

1 2,966,102 Patented Dec. 27, 1 960 ICC Fig. 3 is a similar view takenalong theline 3-3 showing the tripper and the kicker, including itsmounting;

Fig. 4 is a similar view taken along the line 44 showing in detail meansfor controlling the diaphragm;

Fig. 5 is a similar view taken along the line 5-5 showing in detailelements of the shutter including the tripper and latch, andthemountingthereof;

Fig. dis a similar view taken along the line 66 showing a rebound springand means for moving said spr ng in and out of position to engage theshutter blade;

Fig. 7 is a diagrammatic plan view with partsbroken away of the shutterof Fig, 1, the elements thereof-1n position just prior to release of thetripper and commencew ment of an exposure cycle;

Fig. 8. is a similar view with the elements shown in position after theshutter blade had been rotated, the latter being retained at timeexposure position;

Fig. 9 is a diagrammatic, fragmentary plan view ofanother shutterassembly embodying the present invention, the rear housing and itsassociated elements being removed, and the shutter assembly beingviewed-from the focal plane of the camera with the elements oftheshutter being illustrated in their normal position of rest;

Fig. 10 is a similar view of theshutter of Fig. 9 with the elementsthereof positioned so that the tripper is about to be. released tocommence an exposure cycle and eifect the rotation of the shutter blade;and

i Fig. 11 is a similar view of the shutter of Fig. 9 where the shutterblade has just been rotated, and-is retained at time exposure position.

In accordance withthe present invention there is pro vided. a novel.shutter. structure comprising, as elements thereof, an aperture-coveringmeans or shutter blade mounted for relatively free movement, and animpulse member or kicker arm for imparting an impact to said shutterblade to move said blade to an aperture-uncovering, position. Means are,provided for moving the kicker arminto a cocked position wherein it isretained by a latch until released for impact with a portion of theshutter blade. There is provided an inertia tripper adapted to engagethe latch, releasing the kicker arm. The inertia tripper is mounted forsubstantially free rotary movement and is normally retained by atriggeradapted to release the inertia tripper for movement when thekicker arm has been moved into its cocked position. Means for completingan electrical circuit to energize a flash-producing means is renderedoperable by the action of the inertia tripper, the latter being adaptedto engage the latch, releasing the kicker arm at a predeterminedinterval after the flash-producing means is rendered operable. andthereby synchronizing the operation of said means with the operation ofthe shutter. It is to be understood that the term shutter bladeis usedherein in a generic sense to cover any type of closure element which isoperative either alone or together with other elements to effect theclosure of an exposure aperture in a camera, and that the term inertiavtripper is also intended to be generic in its scope and to include flywheels, solid disks, counter-balance arms, etc. which when actuatedpossess sufiicient kinetic energy to coact with or engage one or moreelements of the shutter mechanism and render the same operable.

Referring now to the drawings, wherein like numerals denote like parts,there is shown in Figs. 1 through 6 one form of shutter mechanismcomprehended by the present invention, the associated. elements of whichare represened as they would appear from a position in front of thecamera. Directions ofthe rotation and movement of the associatedelements. as hereinafter described are those which would be observedwhen said elements are viewed r m he. above-des ribed position, thedescri tive lan-v guage being in accordance with said point ofobservation.

As a means for enclosing and mounting the operative elements of theshutter mechanism, there is provided a housing including a front portion(not shown) and a rear or base portion generally indicated at 12, andhaving a lens aperture 14. A suitable aperture control means may beprovided for association with said lens aperture, said means preferablycomprising a disk-type diaphragm 16 shown in Fig. 1 and having aplurality of apertures therein. Diaphragm 16 is rotatably mounted topermit movement of any one of apertures 17 into operative alignment withlens aperture 14. A bracket 18 suitably secured to base portion 12 isprovided with a formed-up spindle 20 on which is mounted diaphragm 16,the latter having a suitable opening 22 in its center for receivingspindle 20. The diaphragm is retained on spindle 20 by spider 24 havinga central body portion 26 secured to spindle 20 by screws 28 and threeresilient legs 30 adapted to bear upon the surface of the diaphragm. Asa means for rotating the diaphragm and for operatively aligning any oneof the apertures 17 adjacent lens aperture 14, there is provided atoothed peripheral portion of diaphragm 32 forming a gear, a pinion 34meshed with said gear, and a control knob 36 rigidly attached to saidpinion by a shaft 38 journaled in the shutter housing. A detent spring44 secured to said housing engages a detent notch 42 in disk 40 mountedon shaft 38 for releasably holding any one of the apertures 17 indiaphragm 16 in operatively aligned position.

To control the exposure through the lens aperture 14 of the shutter,there is provided a shutter blade 46 mounted at one end forsubstantially free rotary movement in and out of aperture-coveringpositions and having an aperture-covering portion 46a and a projectinglug 50 on its other extremity for cooperating with the shutteractuatingmeans. The shutter blade is secured to a hub 52 mounted on a shaft 54intermediate its ends, shaft 54 being journaled at one end in a suitablebearing 56 formed in housing base portion 12 and journaled adjacent itsother end in bracket 18.

For holding the shutter blade in an aperture-covering position, that is,with aperture-covering portion 46a positioned to obstruct the passage oflight through lens aperture 14, one edge of shutter blade 46 is providedwith a rolled portion 48 of some magnetic material and is adapted to bebrought against and retained by a magnet 58 which defines the aforesaidclosed position of the shutter blade. Magnet 58 is secured to aresilient support arm 60 having a flanged base portion 62 at one end bywhich it is secured to bracket 18. Support arm 60 is biased towardshutter blade 46 and is held at a predetermined position by a somewhatrigid arm 64 toward which it is biased, arm 64 having a flanged baseportion 66 by which it is secured to bracket 18. Magnet 58 mounted onarm 60 comprises means for preventing the rebound of shutter blade 46once contact of portion 48 and magnet 58 has been established, magneticforce exerted upon portion 48 by magnet 58 being adapted to thispurpose. Support arm 6!) acts as a shock absorber for the magnet bypermitting magnet 58 to move slightly under an impact of shutter blade46 and thus absorb the kinetic energy of the shutter blade when thelatter returns to a position of rest. Arm 64 in turn serves to absorbthe kinetic energy of the shutter blade transmitted to support arm 60and to dampen the vibration of the latter.

For producing an exposure of accurately controlled duration, there isprovided a kicker means, to be more fully described, for imparting animpulse to the shutter blade for rotating said blade in acounterclockwise direction uncovering lens aperture 14, the left handsurface 50a of lug 50 being suitable for receiving said impulse. Inaddition to means against which a force for rotation may be applied, lug50 serves as a contributing means for determining the direction andextent of rotation of '4 the shutter blade in the following manner. Theextent of counterclockwise rotation of shutter blade 46 when actuatedfor movement by the kicker means is limited by contact of the lug 50with a rebound spring 68 mounted so as to intersect right hand surface50b of lug 50 during the arcual movement of the latter. Rebound spring68 may be formed of any suitable resilient material and, as shown inFig. 1, preferably comprises a resilient base portion 68a secured tohousing portion 12 and an engagement portion 68b adapted to engage lug50 on shutter blade 46. It will be seen that the measure ofcounterclockwise rotational movement of the shutter blade from theclosed position shown in Fig. 1 and consequently the exposure time ofthe shutter is determined by the arcual distance initially separatinglug 50 with a rebound spring 68, by the mass and velocity of therotating shutter blade, and by the deflection characteristics of therebound spring 68 under a load caused by impingement of lug 50thereupon. A second rebound spring 70 may be positioned in the arcuatepath of movement of lug 50, thus increasing the length of travel of theshutter blade when the first spring is removed from its path and therebyincreasing the interval during which the aperture is uncovered. Further,it will be apparent that the speed of rotation of the shutter bladethrough a single exposure cycle comprising counterclockwise andclockwise rotation is substantially predetermined by such factors as themagnitude and characteristics of delivery of the force applied to lug 50for initiating its counterclockwise rotation, by the mass of the shutterblade, by the deflection characteristics of a rebound spring and by theamount of friction existing between shaft 54 and bearings in which it isjournaled.

Means are provided for positioning engagement portion 68b of reboundspring 68 out of the arcuate path of lug 50, this means comprising aresilient arm 72 secured to the shutter housing and having acam-following portion 72a adapted to coact with cam 74. The extremity ofarm 72 is provided with turned-down tab 72b adapted to engage reboundspring 68 and deform the latter so as to move engagement portion 68bthereof from the path of lug 50 when cam 74 coacts with cam-followingportion 72a of said arm to move the latter to the right. Cam 74comprising a plate secured to diaphragm 16 is formed as shown having anengagement portion 74a adapted to coact with cam-following portion 72aof arm 72. The second rebound spring 70 is secured to housing portion 12with a portion of said spring extending into the path of lug 50. It willbe apparent that the length of arcuate travel of lug 50 can be varied bymoving spring 68 into or out of the path of said lug thus varying theshutter speed. In Fig. 1 the position of the elements shown represents asetting of rebound spring 68 for a minimum shutter speed, that is asetting at which lug 50 will travel a maximum arcual distance to andfrom rebound spring 70 and during which time shutter blade 46 willuncover aperture 17. It is further apparent that the elements are setfor maximum shutter speed when rebound spring 68 is superposed in thearcuate path of lug 50 so that the latter will travel a minimum arcualdistance and shutter blade 46 will uncover aperture 17 for acomparatively brief time. A particular diaphragm aperture in exposureposition coupled with a correlated setting of either rebound spring 68or 70 yields a predetermined exposure value. A plurality of appropriatenumbers (not shown) indicating these predetermined exposure values areinscribed circumferentially on the surface of diaphragm 16 adjacent itscentral portion, these numbers being visible through a suitable openingor window (not shown) in the front portion of the housing.

The actuating mechanism for the shutter blade is illustrated in Figs. 1and 7, Fig. 1 showing the elements in a position of rest and Fig. 7showing the elements in a cocked position substantially that which wouldprevail at mosaics the instant when the inertia tripper is about to bereleased by the trigger to initiate an exposure cycle. As a means forimparting an impulse to the shutter blade, there is provided a kickerarm 76 having a pair of centrally located flanges 78 on which it ispivotally mounted on pin 80 and an engagement portion 76a at oneextremity adapted to contact lug 5% on the shutter blade to apply animpulse thereto. The kicker arm 76 is biased for clockwise rotation by atension spring 82 attached at its ends respectively to a flange 34 onthe other extremity of said kicker arm and to a bracket 86 secured tohousing portion 12. For varying the tension of spring 82 andconsequently the driving impulse imparted to the shutter blade, bracket86 is provided with a plurality of notches adapted to retain spring 82.In order that kicker arm 76 may be held in a cocked position by a latch88, there is provided on said kicker arm a tab '76!) adapted to beengaged by a portion of said latch. At its cocked position kicker arm 76is adapted when released to rotate in a clockwise direction, engaginglug 5t and transmitting a driving force to said lug for a brief period.it will be seen in the aforesaid relation of elements that clockwiserotation of kicker arm '76 causes counterclockwise rotation of shutterblade 16, rotational force being continuously transmitted by said kickerarm to said lug until divergence in the arcual movement of said shutterblade and kicker arm due to separate pivotal mountings thereof breakstheir contact with one another. Under the impetus initially supplied bykicker arm 76, the shutter blade continues to rotate in acounterclockwise direction until it impinges either rebound spring 68 orspring 70 and its direction of rotation is reversed thereby aspreviously described.

Latch means are provided for releasabiy holding kicker arm 76 at itscocked position and in the form shown comprises a latch arm 88 mountedat one end on hub 89 pivotally mounted on pivot pin 9i} and having anengagement portion Stia formed to engage tab 7612 on kicker arm 76.Resilient means such as a torsion spring 92 coiled around pivot pin 96;are provided for urging latch arm 88 in a clockwise direction to engagekicker arm '76, one end of said torsion spring being retained in notch88b formed in latch arm 88.

Means are provided for mounting kicker arm '7(, for moving said kickerarm into a cocked position and for operating the shutter mechanism. inthe form shown this means comprises a generally C-shaped kicker-releasearm indicated at 94, pivotally mounted at pin on housing 12 above lensaperture 14- and having an end portion 94a extending through a slot 98in the bottom portion of said housing, said end portion 94a beingengageable either manually or by a suitable linkage means for movementin a counterclockwise direction (to the right) for operating the shuttermechanism. Release arm 94 is normally biased to the left by tensionspring $2 secured to kicker arm 76, which is in turn pivotally mountedon said release arm. There is provided, as a limit stop for theclockwise rotation of kicker arm 7s, a turned-up tab 94b on release arm94.

In accordance with the present invention, there is provided asubstantially tree-moving inertia tripper 1% for releasing latch arm 88from engagement with kicker arm 76 in its cocked position. in the formshown, inertia tripper we generally comprises a yokelike member having afirst arm or inertia portion Mil-a of substantial mass, a second oractuating arm 104, and a connecting member 1% joining the two arms. Theactuating portion 104 has at least a portion lthia adapted to engage aturned-down tab tide on latch arm 88 to release the latter fromengagement with the kicker arm. Tripper ltitl is rotatably mounted onthe housing on pivot pin 90, arm portions ltitia and ltldbeing journaledthereon. As a means for biasing the inertia tripper in acounterclockwise direction, there is provided a tension spring 106secured at one of its ends by stud 108 to inertia-portion- 100a and atits other end to pivot pin on kicker re lease arm $4.

As a means for retaining inertia tripper and for releasing the latter toinitiate an operative cycle of the shutter mechanism when the kicker armhas been moved to its cocked position, there is provided a trigger armformed as shown and generally indicated at 110. Trigger arm is securedto hub 112, pivotally mounted on pin 114 secured in housing portion 12and is normally biased in a clockwise direction by such means as atorsion spring 115 coiled around pin 114 and retained at its extremitiesin notch 116a in trigger arm lit), and tab 18:: turned up from bracket18. Further contributing to the force urging the trigger in a clockwisedirection is torsion spring 92 one end of which is retained in notch11Gb formed in trigger arm 110 and its other end being retained aspreviously described by latch 82 A slot 110a is formed in trigger arm110 through which pivot pin 90 extends, said pin and said slotcooperating to limit pivotal movement of said trigger arm for retainingtripper 100 against the bias of spring 1%. Trigger arm llti is providedwith an engagement portion ltltid adapted to engage connecting member1432 of said tripper. The trigger is also provided with a secondengagement portion lltie adapted to be engaged by a turned-up flange 940on kicker release arm 94 for pivoting the trigger in a counterclock wisedirection to release tripper 166. A turned-down tab 110 on trigger armtit) serves as a limit stop restrict+ ing the pivotal movement of latch88 when kicker arm '76 is released, said turned-down tab 110 on saidlatch 11d being adapted for engagement with tab 880 on the latch arm.

Means are provided for completing an electrical circuit to a photo flashlamp (not shown) in synchronism with the operation of the shuttermechanism. This means comprises, in the form shown, a pair of conductingarms 118 and 124 secured to housing portion 12. Arm 118 suitably securedto said housing portion and insulated therefrom is connected by a leadwire 121 to a fiash receptacle (not shown) of conventional designmounted on the camera. Arm 12% mounted on said housing portion andgrounded therein is biased toward arm 118 so as to contact the latterwhen means holding arm 120 are disengaged therefrom. As a means forcompleting said flash lamp circuit and actuating the shutter blade at apredetermined interval thereafter, connecting member ltiZ of inertiatripper 1% is adapted to engage arm lid to hold the latter away fromcontact with arm 118 until the tripper is released for rotation, andthen allow the two arms to contact one another completing the flash lampcircuit.

In order to operate the shutter, portion 94a of kicker release arm 94-is engaged by the operator and moved to the right so that arm 9 isrotated in a counterclockwise direction against the bias of spring 82.This counterclockwise rotation of kicker release arm 94. moves thekicker '76 mounted thereon upward and to the right toward shutter blade46, latch 88 engaging said kicker and being rotated thereby in acounterclockwise direction around pivot pin 90 against the bias ofspring 92. In Fig. '7 it can be seen that kicker '76 has been moved intoa position behind lug 5t} so that it is capable of transmitting animpulse to shutter blade 46 when said kicker is released. At this pointkicker 76 is held by latch portion 3&1 against the bias of spring 82,and an additional counterclockwise movement of latch 88 against the biasof spring 92 is required in order to release said kicker. Continuedcounterclockwise rotation of kicker release arm 94 past the positionshown in Fig. 7 causes turnedup flange 94c thereon to engage portionlltle of trigger lit to pivot the latter in a counterclockwise directionagainst the bias of springs 92 and 116. As trigger 110 is pivoted in acounterclockwise direction, engagement portion 110d thereof is withdrawnfrom engagement with connecting member 102 of tripper 100, permittingthe latter to rotate in a counterclockwise direction under the bias ofspring 106. During the initial period of rotation of tripper 1100,contact arm 120 restrained thereby is permitted to contact arm 118towards which it is biased and thus complete the circuit to a flashlamp. Tripper 100 continues to rotate until actuating portion 104a ofactuating arm 104 strikes tab 880 on latch 88, pivoting the latter in acounterclockwise direction to release kicker arm 76 therefrom. Kickerarm 76 then rotates in a clockwise direction under the bias of spring 82so as to deliver a sharp impact to lug 50 rotating the shutter blade.The force of this initial impact may be adjusted by varying the tensionof spring 82, adjustments being made by engaging a portion of spring 82in a particular one of said notches in said bracket 86.

After tripping latch 88, tripper 1% comes to rest with the edge 1114b ofactuating arm 164 of said tripper bearing against the heel of flange 940on kicker release arm 94. Removal of the operative force exerted on saidrelease arm 94 permits said arm to return under the bias of spring 82 tothe position of rest as shown in Fig. 1, the heel of flange 94c bearingagainst said edge 1494b of tripper arm 104, rotating the tripper in aclockwise direction against the bias of spring 106 to the position ofrest in Fig. 1. Trigger 110, urged to the left by springs 92 and 116,then engages connecting member 102 to retain tripper 100 in the saidposition of rest.

Means are provided for holding the shutter blade in anaperture-uncovering position during time exposures and, in the formshown in Fig. 1, generally comprise a member movable into the path ofthe shutter blade, this member being effective to prevent the returnmovement of the shutter blade to aperture-covering position. This meansis adapted to manual setting for a bulb exposure" and remains at thatsetting after it is used. A time exposure latch indicated generally at122 comprises a resilient latching arm 124 having a shutter engagementportion 124a and an actuating portion 124]). Latching arm 124constitutes the connecting element of a yoke-shaped member having legs126 and 128, said legs being pivotally mounted on the eccentric shank130 of a manually engageable control knob 132 journaled into housingportion 12. Leg 126 is provided for strength and rigidity while leg 128is formed as shown having an extended toe portion 128a engageable with aturned-up tab 94d on kicker release arm 94. The time exposure latch isrendered operative by pivoting control knob 132, and the eccentric shank130 thereof, approximately 90 in a counterclockwise direction so as tomove legs 126 and 128, mounted thereon, to the left as shown in Fig. 8.When kicker release v arm 94 is pivoted in a counterclockwise direction,tab 94d is moved (to the right) out of engagement with toe portion 128aand another turned-up tab 94a on said release arm engages actuatingportion 12417 of latching arm 124, pivoting the latter in acounterclockwise direction and interposing engagement portion 124a ofarm 124 in the arcual path of lug 50. During the counterclockwiserotation of shutter blade 46, portion 124a of arm 124 is brushed asideby lug 5%, arm 124 then springing inward (to the left) so that portion124a intercepts lug 50 during the return rotation of shutter blade 46,thereby precluding further rotation of the latter. It will be understoodthat the deflection characteristics of latching arm 124 are such as tocause no appreciable diminution in speed of counterclockwise rotation ofthe shutter blade, thus insuring accurate time exposures. Means forrotating latching arm 124 in a clockwise direction to release theshutter blade comprise said toe portion 126a and tab 94d on release arm94, the curved edge 1281) of tee portion 128a coacting with tab 94d topivot time latch 122 when release arm 94 is moved in a clockwisedirection (to the left). In order to return shutter blade 46 to anaperture-covering position after release by latching arm 124, shutterblade 46 is biased against latching arm 124 by torsional hair spring 134connected respectively to collar 136 on the end of shaft 54 and spider24. The hair spring has substantially no effect upon the overall shutterspeed during a given rotational cycle of the shutter blade, inasmuch assaid hair spring, while resisting shutter rotation in a counterclockwisedirection, accelerates rotation of the shutter blade in a clockwisedirection, one force substantially canceling the other during thecomplete shutter cycle. The time exposure latch may be returned to aninoperable or instantaneous exposure position by rotating control knob132 approximately in a clockwise direction. For retaining control knob132 at either an instantaneous or bulb exposure setting, there isprovided a resilient retaining arm 138 secured to the housing andadapted to bear against suitably formed fiat portions 132a on thecontrol knob.

A shutter-actuating mechanism comprising another embodiment of theinvention is illustrated in Figs. 9, l0 and 11, Fig. 9 showing theelements in a position of rest Fig. 10 showing the elements at aposition substantially that which would prevail at the instant beforethe shutter blade is about to commence a given exposure cycle, and Fig.11 showing substantially the position of the elements after the shutterblade has commenced an exposure cycle, said shutter blade beingillustrated as being retained in open position by a time latch generallyindicated at 439. It is understood that the shutter comprising thisembodiment of the actuating mechanism includes, in addition thereto, theshutter structure and associated elements of either the aforementionedcopending application or the herein disclosed shutter. The shutter bladeand actuating mechanism therefore are mounted on a housing the frontportion of which is indicated at 454.

As a means for imparting an impulse to a shutter blade 440 to rotate thesame from an aperture-covering position where it is retained by magnet441, there is provided a kicker arm 442 having a central portion 442a atwhich it is pivotally mounted on pin 444 and an engagement portion 4421;at one end adapted to contact lug 446 on shutter blade 440 to apply animpulse thereto. The other end 442:: of kicker arm 442 is adapted forengagement by a latch 448 for retaining said kicker arm in its cockedposition. The kicker arm 442 is biased for clockwise rotation by atension spring 456 attached at its ends, respectively, to the kicker armat 442:! and to block 452. As a means for adjusting the tension ofspring 452 to vary the driving impulse imparted by the kicker arm to theshutter blade, block 452 is secured to housing 454 by an adjustablescrew 456 permitting variation of the position of the block.

As a means for releasably retaining the kicker arm in its cockedposition, there is provided a generally yokeshaped latch 448 having across member 458 at which it is pivotally mounted on pin 46% secured tohousing 454, a latch arm 462 and a curved tripper engagement arm 464. Atorsion spring 465 coiled around pin 46%) acts to bias latch 448 in acounterclockwise direction so that latch arm 462, having a hook portion462a formed as shown, bears against the end of engagement portion 4420of kicker arm 442, and hook portion 462a engages the end of portion 4420of said kicker arm to hold the latter at its cocked position.

For mounting kicker arm 442 and moving said kicker arm into its cockedposition, there is provided a kicker release arm 466 pivotally mountedin the housing on pin 468 and formed as shown having an end portion 466aextending through a slot in the housing. Kicker arm 442 is mounted onthe other end portion 46612 of release arm 466 and end portion 466a isengageable either manually or by suitable linkage means for movement ina clockwise direction for moving kicker 442 into cocked position withengagement portion 44217 adjacent lug 446 on shutter blade 440. Aturned-down tab 466a on end portion 466]; of release arm 466 is providedas a limit stop for the rotation of kicker arm 4-42. Release arm greasesg; 466 is normally biased in a counterclockwise direction by a torsionspring 470 coiled around pin 468.

Means are provided for releasing latch 448 from engagement with kickerarm 442 and, in accordance with the present invention, comprises afree-moving inertia tripper generally indicated at 472. Tripper 472 ispivotally mounted at its central portion on pin 474 secured to housing454 and includes a trigger engagement notch 472a adjacent'one end and acam portion 472b comprising its other end and adapted to coact with arm464 of latch 448 to cause the latter to release the kicker arm. Tripper472 is normally biased for rotation in a clockwise direction by atorsion spring 476 coiled around pin 474 and, when released forrotation, comes to rest against the bottom portion of housing 454.

As a means for retaining inertia tripper 472 and for releasing the sameto initiate an operative cycle of the shutter mechanism, there isprovided a trigger comprising'an angular arm 478 mounted at its centralportion on pin 48% secured to housing 454. One end portion 478a oftrigger 478 is adapted for engagement with notch 47211 in tripper 472for retaining the latter while the other end portion 47% of trigger 478is adapted to be engaged by a turned-down tab 466a on release arm 466for pivoting the trigger in a clockwise direction to disengage endportion 478a thereof from notch 472a 011 tripper 472, releasing thelatter for rotation. As a means for normally biasing trigger 478 in acounterclockwise direction for holding said trigger end portion 478a inengagement with notch 472a, there is provided a torsion spring 482coiled around pin 480.

Means are provided for completing an electrical circuit to a photo flashlamp (not shown) in synchronisrn with the operation of the shuttermechanism. This means comprises, in the form shown, a pair of conductingarms 484 and 486 secured to housing 454. Substantially rigid arm 484suitably secured to said housing and insulated therefrom is connected bya lead wire to a flash receptacle (not shown) of conventional designmounted on the camera. Arm 486 of resilient material mounted on saidhousing portion and grounded therein is biased toward arm 484 so as tocontact the latter when means holding arm 436 are disengaged therefrom.As a means for completing said flash lamp circuit and actuating theshutter blade at a predetermined interval thereafter, cam portion 47212of inertia tripper 472 is adapted to engage and hold arm 486 away fromcontact with arm 484 until the tripper is released for rotation.

For operating the shutter mechanism, end portion 466a of kicker releasearm 466 is engaged by the operator and pressed downward, pivoting saidarm in a clockwise direction and thereby moving kicker 442 mounted onthe other end 466b thereof upward and causing end 4420 of kicker arm 442to be engaged by hook 46211 on latch 462'. Continued clockwise rotationof release arm 466 results in both pivoting kicker 442 in acounterclockwise direction and moving the same until it is in a posinon(as shown in Fig. to deliver an impact to lug 446 when released. At thispoint the continued rotation of arm 466 causes turned-down tab 46642 onarm 466 to engage end portion 4731) of trigger 478, rotating the latterposition of tripper 472 and latch 448 at substantially this instantbeing illustrated in Fig. 11. Cam portion 472b'coacts with arm 464 topivot latch 448 in a clockwise direction, thereby disengaging hook 462afrom engagement portion 442:: of kicker 442, releasing the latter forrotation under the tension of spring 450. After 10 kicker 442 isreleased for impact with lug 446 on shutter blade 446, kicker 442 andtripper 472 continue to rotate until said kicker comes to rest againsttab 466a and said tripper comes to rest against a portion of housing454.

At this point, end portion 466a of release arm 466 may be released bythe camera user, permitting arm 466 to rotate in a counterclockwisedirection under the bias of spring 470 for returning the operativeelements of the shutter-actuating mechanism to their initial position ofrest (Fig. 9). Tab 466a on arm 466 is disengaged from end portion 478E:of trigger 478, permitting the latter to rotate in a counterclockwisedirection until end portion 473a comes to rest against tripper 472. Tab466d on arm 466 engages tripper 472, rotating it in a counterclockwisedirection until notch 472a is engaged by end portion 478a of trigger 78.Kicker 442 mounted on arm 466 is also returned to its original position,end 4420 of said kicker coacting with engagement arm 462 to deflectlatch 448 until end 4420 is engaged by hook 462a.

It is evident that the use of a free-moving inertia element or stripperwhich is independent from those elements contributing to the impulseapplied to the shutter blade for rotating the latter provides means forfiring a flash lamp in accurate synchronism with the action of theshutter blade. The duration of the time interval between the completionof the flash lamp circuit and the application of an impulse to theshutter blade can be accurately controlled and varied in accordance withthe illumination characteristics of the particular flash lamp, therebyinsuring that the camera aperture is fully uncovered when the flashreaches peak intensity, and that this peak is reached at any desiredinstant during the shutter exposure cycle. The duration of the timeinterval may be adjusted by varying the mass and thereby inertiacharacteristics of the tripper, by varying the shape or location ofthose portions of said tripper which coact with elements of the shutterto render them operative, by varying the location of shutter elements soas to increase or decrease the angle of rotation of the tripper, byvarying the tension or resiliency of the spring which actuates thetripper, or by any combination of the above rethods. It is furtherevident that a flash lamp firing switch, comprising two contacts biasedtowards one another and which does not depend on the kinetic energy of amoving element of the shutter to close the contacts, provides for thepositive closing of the flash lamp circuit with low resistance contactof substantial duration. This arrangement has obviated the danger ofreopening of the circuit before the flash bulb is fired.

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

l. A camera shutter comprising, in combination, a casing including anexposure aperture, a blade movably mounted on said casing and normallylocated in a position covering said aperture, an impulse member, meansfor driving said impulse member so as to deliver an impact to said bladeto impart an aperture-uncovering movement to said blade, a latch forretaining said impulse member in a set position in readiness to deliveran impact to said blade, means providing a normally open electricalcircuit for a flash lamp, and means for closing said circuit and forreleasing said latch after a predetermined interval following closing ofsaid circuit, the last-named means including a movable inertia memberhaving a predetermined rotational inertia, said interval beingestablished as a function of said rotational inertia, said inertiamember being coupled with said means providing said circuit for closingsaid circuit duringinitial movement of said inertia member, said latchbeing located in the path of movement of said inertia member so thatsaid inertia mem- 11 ber coacts with said latch to disengage the latterfrom said impulse member for releasing said impulse member to deliver animpact to said blade.

2. A camera shutter comprising, in combination, a casing including anexposure aperture, a blade movably mounted on said casing and normallylocated in a position covering said aperture, an impulse member, meansfor driving said impulse member so as to deliver an impact to said bladeto impart an aperture-uncovering movement to said blade, a latch forretaining said impulse member in a set position in readiness to deliveran impact to said blade, means providing a flash lamp circuit and aswitch in said circuit having at least one movable contact, and meansfor closing said switch and for releasing said latch after apredetermined interval following closing of said switch, the last-namedmeans including a movable inertia member having a predeterminedrotational inertia, said interval being established as a function ofsaid rotational inertia, said movable contact and said latch beinglocated in the path of movement of said inertia member whereby saidmember coacts with said contact during its initial movement for closingsaid switch and thereafter coacts with said latch for disengaging saidlatch from said impulse member and releasing the latter to deliver animpact to said blade.

3. A camera shutter comprising, in combination, a casing including anexposure aperture, a shutter blade mounted for rotary movement on saidcasing, means for retaining said blade in a position covering saidaperture, an impulse member, a first spring for driving said impulsemember so as to deliver an impact to said blade to impart anaperture-uncovering movement to said blade, a latch for retaining saidimpulse member in a set position in readiness to deliver an impact tosaid blade, means providing a flash lamp circuit and a switch in saidcircuit having at least one movable contact, and means for closing saidswitch and, after a predetermined interval following closing of saidswitch, releasing said latch, the lastnamed means including an inertiamember mounted for rotary movement and a second spring for driving saidinertia member, said inertia member having a predetermined rotationalinertia, said interval being predetermined as a function of saidrotational inertia, said movable contact and said latch being located inthe path of rotary movement of at least a portion of said inertia memberwhereby said member coacts with said contact during its initial movementfor closing said switch and thereafter coacts with said latch todisengage said latch from said impulse member and release the latter todeliver an impact to said blade.

4. A camera shutter comprising, in combination, a casing including anexposure aperture, a blade movably mounted on said casing and normallylocated in a position covering said aperture, an impulse member fordelivering an impact to said blade to impart an apertureuncoveringmovement thereto, a latch for retaining said impulse member in a setposition in readiness to deliver an impact to said blade, meansproviding an electrical flash lamp circuit and a switch in said circuithaving two contacts, at least one of said contacts being movable withrespect to and biased toward the other of said contacts, and means forclosing said circuit and, after a predetermined interval followingclosing of said circuit, releasing said latch, the last-named meansincluding a movable inertia member having a set position wherein saidmember engages said one contact and retains it apart from said othercontact, said inertia member having a predetermined rotational inertiafor determining said interval, said latch being located in the path ofmovement of said inertia member so that said inertia member coacts withsaid latch to disengage the latter from said impulse member, releasingsaid impulse member to deliver an impact to said blade, said inertiamember being adapted, during its initial movement, to release said onecontact so that it moves toward said other contact, closing saidelectrical circuit prior to release of said impulse member.

5. A camera shutter comprising, in combination, a casing including anexposure aperture, a blade movably mounted on said casing and normallylocated in a position covering said aperture, an impulse member, meansfor driving said impulse member so as to deliver an impact to said bladeto impart an aperture-uncovering movement to said blade, a latch forretaining said impulse member in a set position in readiness to deliveran impact to said blade, means providing an electrical flash lampcircuit including a switch having two contacts at least one of which ismovable with respect to and is biased toward the other contact, amovable inertia member having a set position wherein said inertia memberengages said one contact for retaining said one contact apart from theother of said contacts, said inertia member having a predeterminedrotational inertia for determining said interval, and means for drivingsaid inertia member so that it moves from engagement with said onecontact, allowing said one contact to move toward the other of saidcontacts for closing said electrical circuit, said latch being locatedin the path of movement of said inertia member whereby said membercoacts with said latch for disengaging said latch from said impulsemember and releasing the latter to deliver an impact to said blade.

6. The shutter of claim 5 wherein said switch comprises a substantiallyrigid arm mounted on said housing and insulated therefrom and aresilient arm mounted on said housing and grounded therein, saidresilient arm being biased toward said rigid arm so as to contact thelatter for completing the electrical circuit.

7. The shutter of claim 5 wherein said inertia member includes a camportion adapted to coact with said one contact for moving said contactand opening said switch when said inertia member is moved into setposition, and a striker portion adapted to engage said latch for movingsaid latch so as to release said impulse member.

8. A camera shutter comprising, in combination, a casing including anexposure aperture, a blade movably mounted on said casing and normallylocated in a position covering said aperture, an impulse member, meansfor driving said impulse member so as to deliver an impact to said bladeto impart an aperture-uncovering movement to said blade, a latch forretaining said impulse member in a set position in readiness to deliveran impact to said blade, means providing an electrical fiash lampcircuit including a switch having two contacts at least one of which ismovable with respect to and is biased toward the other contact, amovable inertia member having a set position wherein said inertia memberengages said one contact for retaining said one contact apart from theother of said contacts, said inertia member having a predeterminedrotational inertia for determining said interval, means for driving saidinertia member so that it moves from engagement with said one contact,allowing said one contact to move toward the other of said contacts,closing said electrical circuit, said latch being located in the path ofmovement of said inertia member whereby said member coacts with saidlatch for disengaging said latch from said impulse member and releasingthe latter to deliver an impact to said blade, and means forsimultaneously engaging and moving said impulse member into set positionand moving said inertia member into set position against the bias ofsaid one contact for opening said switch.

References Cited in the file of this patent UNITED STATES PATENTS2,355,825 Schwarz Aug. 15, 1944 2,439,417 Castedello Apr. 13, 19482,490,755 Hutchison Dec. 6, 1949 2,662,457 Fairbank Dec. 15, 1953

